Methods and apparatus for rfid communications in a process control system

ABSTRACT

Methods and apparatus for RFID communications in a process control system are disclosed. An example apparatus includes a radio-frequency identification tag operatively coupled to a field device of a process control system. The radio-frequency identification tag has a processor, an onboard memory, and an antenna. The onboard memory stores data received from the field device to be communicated to a radio frequency identification reader. Power for the processor and the onboard memory is to be drawn from control system power provided to the field device.

RELATED APPLICATION

This patent arises from a non-provisional application based on U.S.Provisional Application Ser. No. 61/832,524 filed on Jun. 7, 2013; U.S.Provisional Application Ser. No. 61/951,187 filed on Mar. 11, 2014; andU.S. Provisional Application Ser. No. 61/977,398 filed on Apr. 9, 2014,all of which are hereby incorporated by reference in their entireties.

FIELD OF THE DISCLOSURE

This disclosure relates generally to process control systems and, moreparticularly, to methods and apparatus for RFID communications in aprocess control system.

BACKGROUND

Process control systems, like those used in chemical, petroleum or otherprocesses, typically include one or more process controllerscommunicatively coupled to one or more field devices via analog, digitalor combined analog/digital buses. The field devices, which may be, forexample, instruments, valve positioners, switches and transmitters(e.g., temperature, pressure and flow rate sensors), perform processcontrol functions within the process such as opening or closing valvesand measuring process control parameters. The process controllersreceive signals indicative of process measurements made by the fielddevices and then process this information to generate control signals toimplement control routines, to make other process control decisions, andto initiate process control system alarms.

Information from the field devices and/or the controller is usually madeavailable over a data highway or communication network to one or moreother devices or systems, such as operator work stations, personalcomputers, data historians, report generators, centralized databases,etc. Such devices or systems are typically located in control roomsand/or other locations remotely situated relative to the harsher plantenvironment. These devices or systems, for example, run applicationsthat enable an operator to perform any of a variety of functions withrespect to the process implemented by a process control system, such asviewing the current state of a process, changing an operating state,changing settings of a process control routine, modifying the operationof the process controllers and/or the field devices, viewing alarmsgenerated by field devices and/or process controllers, simulating theoperation of the process for the purpose of training personnel and/orevaluating the process, etc.

SUMMARY

Methods and apparatus for RFID communications in a process controlsystem are disclosed. An example apparatus includes a radio-frequencyidentification tag operatively coupled to a field device of a processcontrol system. The radio-frequency identification tag has a processor,an onboard memory, and an antenna. The onboard memory stores datareceived from the field device to be communicated to a radio frequencyidentification reader. Power is to be provided to the processor and theonboard memory from control system power associated with the fielddevice.

Another example apparatus includes a radio-frequency identification tagoperatively coupled to a field device of a process control system. Theradio-frequency identification tag operates in a semi-passive mode. Theexample apparatus also includes a power manager operatively coupledbetween the radio-frequency identification tag and the field device. Thepower manager provides power to the radio-frequency identification tagdrawn from control system power of the process control system.

An example method includes powering a radio-frequency identification tagoperatively coupled to a field device of a process control system fromcontrol system power provided to the field device. The example methodalso includes storing data on the radio-frequency identification tagobtained from the field device. The example method further includeswirelessly transmitting the data to a radio-frequency identificationreader.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an example process control systemwithin which the teachings of this disclosure may be implemented.

FIG. 2 illustrates an example manner of implementing the example RFIDdevice of FIG. 1.

FIG. 3 illustrates another example manner of implementing the exampleRFID device of FIG. 1.

FIG. 4 illustrates an example manner of implementing encrypted datarecords in the example RFID device of FIGS. 2 and/or 3.

FIG. 5 illustrates a particular implementation of the example RFIDdevices of FIGS. 2 and/or 3 to be coupled to an actuator via a valvecontroller to control a valve.

FIG. 6 is a flowchart representative of an example method forimplementing the example RFID device of FIG. 2 to wirelessly communicatedata from a field device to a local RFID reader/writer.

FIG. 7 is a flowchart representative of an example method forimplementing the example RFID device of FIG. 3 to wirelessly communicatedata from a field device to a local RFID reader/writer.

FIG. 8 is a flowchart representative of an example method forimplementing the example RFID devices of FIGS. 1, 2, and/or 3 to providedata from a field device requested locally via an RFID reader/writer.

FIG. 9 is a flowchart representative of an example method forimplementing the example RFID devices of FIGS. 1, 2, and/or 3 to providedata to the RFID device associated with a field device generated locallyvia an RFID reader/writer.

FIG. 10 is a flowchart representative of an example method of replacinga first field device in the example process control system 100 with asecond replacement field device using the example RFID devices of FIGS.1, 2, and/or 3 to automatically configure the second replacement fielddevice.

FIG. 11 is a schematic illustration of an example processor platformthat may be used and/or programmed to carry out the example methods ofFIGS. 6-10, and/or, more generally, to implement the example RFIDdevices of FIGS. 1, 2, and/or 3.

DETAILED DESCRIPTION

While field devices located throughout a process control system may bemonitored, along with their corresponding parameters, from a central,remotely located control room, there are circumstances where operators,engineers, and/or other plant personnel are located in the field nearthe field devices such as, for example, during the inspection,maintenance and/or repair of field devices and/or other control elementswithin a process plant. Frequently, maintenance and repair is a plannedand time-driven plant activity dependent upon swift access to detailedplant information. When field devices and/or final control elementsfail, the inability to access technical information necessary tocomplete the repairs while plant personnel are located in the field nearsuch components can result in costly waste and/or lost production. Morereliable equipment and predictive maintenance via prognostic algorithmsare goals in current maintenance concepts that require access to robustmaintenance and repair information.

Such maintenance programs are often plagued with records and partsordering systems that contain misfiled, out-of-date, incomplete and/orinaccurate records. Further, without an integrated enterprise solution,data can be located in multiple physical locations and/or housed inelectronic data records that are not quickly accessible by maintenancepersonnel during a walk-down. As part of a typical walk-down, everypiece of equipment is examined, and nameplate specifications, such asmodel and serial numbers, are recorded. A detailed set of attributes foreach type of equipment also is collected.

Additionally, in maintenance situations where local replacement of afield device is required, device configuration and commissioning canbecome a significant issue. Specifically, field devices that includeembedded microprocessors and/or microcontrollers may have complexconfigurations that require maintenance technicians to referencetechnical data stored remotely throughout the enterprise solution. Inmany such situations, technicians may rely on written records that maynot be up to date and/or may be otherwise incomplete. Further, incircumstances where technicians connect to the enterprise solution toretrieve the needed technical data, access to the data can be slow(e.g., based on the communication protocols implemented throughout theenterprise to convey data). Accordingly, in such situations, among othersituations where plant personnel are local to the field devices, it isdesirable to enable the plant personnel to communicate with the fielddevices that are able to store relevant technical data locally toprovide complete and up to date information without depending upon slowcommunication speeds to retrieve the same information stored at a remotesite.

In some instances, plant personnel carry portable handheld communicatorswith which they may communicate with and/or interrogate a device ofinterest. However, in many such instances, physically connecting aportable communicator device to a field device requires the plantpersonnel to, for example, unscrew and remove a terminal cap of thefield device. As a result, access is typically limited to field devicesthat are out of service because removing a terminal cap from a currentlyoperating field device (i.e. a field device in service) would violateplant safety standards. To overcome this obstacle, intrinsically safewireless transceivers have been implemented to communicate with fielddevices and then wirelessly transmit the data elsewhere, such as, forexample, a handheld wireless receiver carried by nearby plant personnel.

Although wireless transceivers are an improvement, currently knownwireless transceivers suffer from several limitations. For example, manyknown wireless transceivers rely on power from the control system (e.g.,loop power) provided to the corresponding field device to chargebatteries and/or capacitors to power wireless transmissions. As manyfield devices are implemented on a tight power budget as a result of thelow voltage signal provided by the power from the control system,wireless communications by many known wireless transceivers are limitedto periods of time where sufficient power is available and/or after aperiod of time where sufficient power has been scavenged from thecontrol system power provided to the field device. As such, many knownwireless transceivers are not conducive to high speed communicationsand/or transfers of significant amounts of data. Further, some devicesmay use solar power to charge capacitors. However, solar power may notalways be reliable depending upon the location and/or environment inwhich the device is being implemented. Additionally, many known wirelesstransceivers are in serial communication with a wired modem associatedwith the particular communication protocol implementing the interactionof field devices within the process control system. As a result, thecommunication speed of the wireless transceivers is limited to thecommunication speed of the corresponding protocol, which can berelatively slow (e.g., the well-known HART protocol is limited to 1200baud). Further, because known wireless transceivers typically rely oncontrol system power to function, wireless transmissions are onlypossible when the process plant is running and the particular fielddevice is not otherwise unpowered (e.g., not placed out of service dueto maintenance). Furthermore, many devices cannot be shipped ortransported with batteries such that when these devices are taken out ofservice to be shipped off for repairs, there is no power source withwhich to communicate with the devices.

The above obstacles are overcome and high speed local communicationswith a field device, among various other advantages, are realizedthrough the implementation of the teachings disclosed herein anddeveloped more fully below. In particular, the teachings disclosedherein achieve wireless communications through the use ofradio-frequency identification (RFID), which is an extremely energyefficient technology. For example, ultra-high frequency (UHF) passiveRFID tags receive power from an electromagnetic field (EMF) generatedfrom a nearby handheld RFID reader (e.g., typically within a distance ofapproximately 30 feet). Semi-passive RFID tags use local power (e.g., abattery) to power internal circuits, but still rely on power from ahandheld RFID reader for communication to the reader. With the relianceon local power for communications, semi-passive RFID tags can havelonger read ranges than passive RFID tags (e.g., up to 90 feet). ActiveRFID tags use local power to power both internal circuits and tocommunicate with a reader. As such, active RFID tags exhibitsignificantly longer transmission ranges (e.g., up to 1000 feet).

Different implementations of RFID technology depend upon variousengineering tradeoffs of features relevant to the particular industry inwhich the technology is being applied. Such tradeoffs are accomplishedby balancing features such as read range, write range, cost, batterylife, service life, allowable temperature range, weather resistance,etc. In the context of the process control industry, some of theperformance parameters of particular interest include long distanceread/write range, high reliability, and large data capacity. To achievelong ranges, far field or ultra high frequency (UHF) RFID technology maybe implemented. However, the longer the range of communications thegreater the limit on memory capacity (if implementing passive RFID tags)or the greater power requirements (if implementing semi-passive oractive RFID tags). Examples disclosed herein achieve certain balancesbetween these features that are suitable to applications within theprocess control industry.

In some disclosed examples, a passive RFID tag is physically andoperatively coupled to a field device within a process control system.Once data from the field device is gathered, in some such examples, theRFID tag may transmit the data to a nearby handheld RFID reader based onpower received from an EMF of the reader. As such, plant personnel localto the field device can wirelessly access data associated with the fielddevice (e.g., data previously communicated from the field device to theRFID tag or an associated memory) in a manner that maintains the plantsafety policy by avoiding the need to unscrew and remove a terminal cap.Additionally, plant personnel can wirelessly access data associated witha field device located beyond safety boundaries and/or otherwise out ofdirect access by plant personnel (e.g., placed up high on a tower orbehind other equipment). Furthermore, in such examples, because the RFIDtag is passive (e.g., does not use any power other than from thehandheld RFID reader), plant personnel may communicate with the RFID tagregardless of power being provided to the corresponding field device.Thus, plant personnel can communicate with the RFID tag when the fielddevice is operating, when the field device or plant is down, and evenwhen the field device is removed from the plant (e.g., for repairs,before installation, etc.). In some examples, plant personnel local tothe field can wirelessly communicate with (e.g., interrogate, calibrate,etc.) the field device with a handheld reader via the RFID tag.

In some disclosed examples, a semi-passive RFID tag is physically andoperatively coupled to a field device within a process control system.In such examples, the RFID tag may draw power from the power provided bythe control system to operate and communicate with the field device. Insome examples, the power is drawn from 4-20 mA analog signals sent alongwires to the field device commonly referred to as loop power. In otherexamples, the power is drawn from wires along a 24 volt digital buscommonly referred to as network power or bus power. As used herein, looppower and network power are collectively referred to as control systempower.

In some examples, the tradeoff between communication range and memorycapacity for semi-passive RFID tags is somewhat alleviated because thesupplemental power source (e.g., control system power) can power thememory and corresponding processor of the tag. In this manner, a highercapacity memory can be used. Further, with the memory and processor ofthe RFID tag being control system powered, an EMF from a handheld RFIDreader can be used to solely power the antenna, thereby achieving longercommunication ranges. For example, a passive RFID tag (that is poweredsolely by an EMF generated by the RFID reader) may have a rangeextending up to about 30 feet, whereas a semi-passive RFID tag (that isbattery assisted or receives other auxiliary power such as controlsystem power) may have a range extending a distance up to about 90 feet.While these ranges are possible, some RFID tags may be characterized bylonger or shorter ranges depending upon the particular RFID tag basedupon other design considerations (e.g., cost, size, etc.).

Thus, by taking advantage of control system power (e.g., in asemi-passive tag implementation), which is available in most all processcontrol system environments, increased memory capacity and increasedcommunication ranges are possible. Furthermore, read ranges near 90feet, as described above, are likely to enable plant personnel to bewithin range of almost any field device regardless of its location(e.g., beyond safety boundaries, up a tower, etc.). Further,semi-passive RFID tags can communicate omni-directionally such thatplant personnel do not have to be at a particular location within thetransmission range to communicate with an RFID tag associated with afield device. Additionally, while semi-passive RFID tags are designed tooperate with supplemented power (e.g., control system power), such tagsmay also be operated in a fully passive mode (e.g., when there is nocontrol system power). However, if higher memory has been incorporatedinto such tags in reliance on the availability of control system power(e.g., the RFID tags are expected to primarily operate in a semi-passivemode), the communication range of the tag when in a passive mode may besignificantly reduced to a short range (e.g., one foot or less). Thus,while communications with such RFID tags are possible without controlsystem power, such communications may be limited to when the handheldRFID reader can be brought next to the field device (e.g., when in frontof a technician for repairs). Thus, the example methods and apparatusdisclosed herein that use the different passive or semi-passiveimplementations present different tradeoffs between memory andcommunication range in settings both where control system power isavailable and where such power may be unavailable. Additionally oralternatively, in some examples, near field communications (e.g., basedon magnetic induction) are used to communicate with an RFID tag that hasno other power source. Such examples, typically involve the RFID readerbeing positioned within a few inches and up to about one foot of theRFID tag. As such, the close proximity in such examples provides greatersecurity as an operator accessing the RFID tag with a reader must beright next to the tag.

Furthermore, while passive RFID tags typically have limited onboardmemory, in some examples, as data is gathered from the field device, thedata is stored in a separate non-volatile memory that is accessible bythe RFID tag when needed based on a request via a portable RFIDreader/writer. By gathering and storing the data in this manner, thedata is effectively cached for quick retrieval without the limitation ofslow communications based on the power consumption requirements of otherknown wireless transceivers and/or based on the requirements of thecommunication protocol implemented within the process control system.Further, the separate non-volatile memory provides extra memory for acorresponding field device, which may be used to store additionalinformation related to the identification, maintenance, and/orcommissioning of the field device to assist in maintaining and/orrepairing faulty devices. In some examples, communications from acentral control room may also be written to the non-volatile memory forretrieval by plant personnel during a walk-down and/or at any othertime. Additionally, in some examples disclosed herein, the RFID tags areassociated with a modem to communicate with the field device, and/or therest of the process control system according to the particularcommunications protocol implemented in the control system (e.g., HART).Further, in some examples, a portable RFID reader/writer can be used toupdate and/or provide additional information to the non-volatile memoryfor subsequent reference and access. Additionally, in some examples thewriting of data to the non-volatile memory and the corresponding accessof the data is implemented using asymmetric cryptography to certifyand/or authenticate the validity of the data. Further, in some examples,the RFID tag is fully active such that the antenna is also controlsystem powered and, thereby, enabled to broadcast signals and achieveeven greater ranges.

FIG. 1 is a schematic illustration of an example process control system100 within which the teachings of this disclosure may be implemented.The example process control system 100 of FIG. 1 includes one or moreprocess controllers (one of which is designated at reference numeral102), one or more operator stations (one of which is designated atreference numeral 104), and one or more work stations (one of which isdesignated at reference numeral 106). The example process controller102, the example operator station 104 and the example work station 106are operatively coupled via a bus and/or local area network (LAN) 108,which is commonly referred to as an application control network (ACN).

The example operator station 104 of FIG. 1 allows an operator, engineer,and/or other plant personnel to review and/or operate one or moreoperator display screens and/or applications that enable the plantpersonnel to view process control system variables, states, conditions,alarms; change process control system settings (e.g., set points,operating states, clear alarms, silence alarms, etc.); configure and/orcalibrate devices within the process control system 100; performdiagnostics of devices within the process control system 100; and/orotherwise interact with devices within the process control system 100.

The example work station 106 of FIG. 1 may be configured as anapplication station to perform one or more information technologyapplications, user-interactive applications and/or communicationapplications. For example, the work station 106 may be configured toperform primarily process control-related applications, while anotherwork station (not shown) may be configured to perform primarilycommunication applications that enable the process control system 100 tocommunicate with other devices or systems using any desiredcommunication media (e.g., wireless, hardwired, etc.) and protocols(e.g., HTTP, SOAP, etc.). The example operator station 104 and theexample work station 106 of FIG. 1 may be implemented using one or morework stations and/or any other suitable computer systems and/orprocessing systems. For example, the operator station 104 and/or workstation 106 could be implemented using single processor personalcomputers, single or multi-processor work stations, etc.

The example LAN 108 of FIG. 1 may be implemented using any desiredcommunication medium and protocol. For example, the example LAN 108 maybe based on a hardwired and/or wireless Ethernet communication scheme.However, any other suitable communication medium(s) and/or protocol(s)could be used. Further, although a single LAN 108 is illustrated in FIG.1, more than one LAN and/or other alternative pieces of communicationhardware may be used to provide redundant communication paths betweenthe example systems of FIG. 1.

The example controller 102 of FIG. 1 may be, for example, a DeltaV™controller sold by Fisher-Rosemount Systems, Inc., an Emerson ProcessManagement company. However, any other controller could be used instead.Further, while only one controller 102 is shown in FIG. 1, additionalcontrollers and/or process control platforms of any desired type and/orcombination of types could be coupled to the LAN 108. In any case, theexample controller 102 performs one or more process control routinesassociated with the process control system 100 that have been generatedby a system engineer and/or other plant personnel using the operatorstation 104 and which have been downloaded to and/or instantiated in thecontroller 102.

As shown in the illustrated example of FIG. 1, the example controller102 may be coupled to a plurality of smart field devices 110, 112, 114via a data bus 116 and an input/output (I/O) gateway 118. The smartfield devices 110, 112, 114 may be Fieldbus compliant instruments,transmitter, sensors, etc., in which case the smart field devices 110,112, 114 communicate via the data bus 116 using the well-knownFoundation Fieldbus protocol. Of course, other types of smart fielddevices and communication protocols could be used instead. For example,the smart field devices 110, 112, 114 could instead be Profibus and/orHART compliant devices that communicate via the data bus 116 using thewell-known Profibus and HART communication protocols. Additional I/Odevices (similar and/or identical to the I/O gateway 118) may be coupledto the controller 102 to enable additional groups of smart fielddevices, which may be Foundation Fieldbus devices, HART devices, etc.,to communicate with the controller 102.

In addition to the example smart field devices 110, 112, 114, coupledvia the I/O gateway 118, one or more smart field devices 122 and/or oneor more non-smart field devices 120 may be operatively coupled to theexample controller 102. The example smart field device 122 and non-smartfield device 120 of FIG. 1 may be, for example, conventional 4-20milliamp (mA) or 0-24 volts direct current (VDC) devices thatcommunicate with the controller 102 via respective hardwired links. Insuch examples, the hardwired links enable the field device 120 tocommunicate with the controller 102 and provide electrical power (e.g.,loop power, network power) to the field device 120.

Additionally, each of the field devices 110, 120, 122 is shown in theillustrated example of FIG. 1 coupled to a corresponding RFID device124. With respect to the smart field devices 110, 122 in the illustratedexample, the corresponding RFID device 124 may convert (e.g., via amodem) outbound data obtained from the field devices 110, 122 (e.g.,parameter values, diagnostic information, etc.) according to aparticular communication protocol associated with the field devices 110,122 (e.g., HART, Profibus, Foundation Fieldbus, etc.) for transmissionto an RFID reader/writer 206 (FIG. 2). Additionally, in some examples,the RFID device 124 may convert (e.g., via the modem) inbound dataobtained from the RFID reader/writer 206 to be transmitted to the fielddevices 110, 122 and/or other components of the process control system100 according to the particular communications protocol. In someexamples, the RFID device 124 does not include a modem and simplyrecords data obtained from the smart field devices 110, 122 and/or thenon-smart field device 120 directly to memory for transmission to theRFID reader/writer 206. In addition to storing and/or communicatingprocess control data, in some examples, the RFID device 124 stores otherinformation (e.g., maintenance records (e.g., alert logs, diagnostictest results, and/or other diagnostic information indicative of theoperational health of the field device), parts lists, serial cardinformation, specification sheet, photographs, etc.) associated with thecorresponding smart field device 110, 122 or non-smart field device 120as described in further detail below. In some examples, such informationis also communicated to the RFID device 124 via the corresponding fielddevice. Additionally or alternatively, in some examples, such data iscommunicated via the RFID reader/writer 206. In some examples,communications between the RFID device 124 and the RFID reader/writer206 are powered by the RFID reader/writer 206 (e.g., the EMF of the RFIDreader/writer 206 powers the RFID device 124). Accordingly, the RFIDdevice 124 enables plant personnel to communicate locally and wirelesslywith the field devices 110, 120, 122 without power consumptionrequirements that may decrease the power efficiency of the processcontrol system (e.g., by drawing on the control system power) and/orincrease maintenance costs (e.g., by requiring the acquisition and/orreplacement of batteries). In other examples, the RFID device 124 is atleast partially powered via the process control system (e.g., in asemi-passive RFID mode), thereby enabling communications over longerranges and allowing for greater memory space. In other examples, theRFID device 124 is fully powered via the process control system (e.g.,in an active RFID mode), to enable the antenna to broadcasttransmissions rather than back scattering a signal from the RFIDreader/writer. In such examples, significantly longer communicationsranges are possible (e.g., up to 1000 feet).

Example manners of implementing the RFID device 124 in accordance withthe teachings described herein are shown and described below inconnection with FIGS. 2 and 3. It should be appreciated that a singleRFID device 124 may be used to interact with more than one of the fielddevices 110, 112, 114, 120, 122 by moving the RFID device 124 from onedevice to another as dictated by the circumstances of the process systemand the particular needs of plant personnel. Additionally oralternatively, as shown in FIG. 1, multiple RFID devices may beconnected to any or all of the field devices 110, 112, 114, 120, 122.More particularly, in some examples, each field device 110, 112, 114,120, 122 (or at least some of the field devices) are coupled to aseparate RFID device 124 and remain coupled to the corresponding RFIDdevice 124 throughout an entire lifecycle, or portion thereof, of thefield device. In some such examples, the RFID device 124 contains anon-volatile memory 208 (FIG. 2) separate from any memory internal tothe corresponding field device 122. In such examples, the RFID device124 is capable of storing serial card data and/or any other dataassociated with the identification, maintenance, configuration, and/oroperation of the field device 122. Typically, the memory within a fielddevice is relatively limited such that much of this information (e.g.,documentation and historical records of maintenance, repairs, partsreplacements, etc.) has been remotely stored at a central maintenancedatabase for the entire enterprise. However, by coupling the RFID device124 with its own non-volatile memory 208 in accordance with theteachings disclosed herein, this information can be accessed quickly andeasily by plant personnel local to the field device (e.g., during awalk-down) with an RFID reader/writer 206. Furthermore, in suchexamples, the information associated with the field device 122 stored onthe RFID device 124 is accessible even when the field device 122 istaken out of service and/or removed from the plant environment (e.g.,when shipped off for repairs). Additionally, as described in greaterdetail below, in some examples, at least some of the information may bestored in an onboard memory of an RFID tag 210 (FIG. 2) within the RFIDdevice 124 such that the information can be accessed without a powersource to the field device 122 (e.g., when the RFID tag 210 isfunctioning in a passive mode).

While FIG. 1 illustrates an example process control system 100 withinwhich the methods and apparatus to communicate with process controlsystem field devices using an RFID device described in greater detailbelow may be advantageously employed, the methods and apparatusdescribed herein may, if desired, be advantageously employed in otherprocess plants and/or process control systems of greater or lesscomplexity (e.g., having more than one controller, across more than onegeographic location, etc.) than the illustrated example of FIG. 1.

FIG. 2 illustrates an example RFID device 200 that may be used toimplement the example RFID device 124 of FIG. 1. In the illustratedexample, the RFID device 200 is connected to the field device 122 of theprocess control system 100 of FIG. 1 (the remainder of which isrepresented by the distributed control system (DCS) block 201). In theillustrated example, the RFID device 200 includes a HART modem 202, amicrocontroller 204 associated with a random access memory (RAM) 207 anda non-volatile memory 208. The RFID device 200 also includes an RFID tag210 that comprises a main RFID processor 212, an RFID onboard memory 214(also a form of non-volatile memory), and an RFID antenna 216. In someexamples, the RFID processor 212, the RFID onboard memory 214, and theRFID antenna 216 are all incorporated onto a single integrated circuit(IC).

In the illustrated example of FIG. 2, the field device 122 is identifiedas a HART-compliant field device. As stated above, the teachings of thisdisclosure may be implemented in connection with a field deviceassociated with any suitable communication protocol (e.g., Fieldbus,Profibus, etc.). However, the following disclosure is explained by wayof example in terms of the HART communication protocol. Thus, as shownin FIG. 2, the HART field device 122 is operatively coupled to the DCS201 via a pair of signal wires 218 (represented by the two solid lines)to communicate according to the HART protocol. In addition totransmitting and receiving control signals over the signal wires 218,the field device 122 also draws its power from the signal wires 218(e.g., the field device is control system powered, which in the contextof the HART protocol means 4-20 mA loop powered and in the context ofthe Fieldbus protocol means 24 V network power). Additionally, in theillustrated example, the RFID device 200 is linked to the signal wires218 such that the HART field device 122 is operatively coupled to theRFID device 200 via the HART modem 202 and to enable the RFID device 200to draw power from the control system power provided via the signalwires 218. In some examples, communications are sent and/or receivedbetween the RFID device 200 and the field device 122. Additionally oralternatively, in some examples, communications are sent and/or receivedbetween the RFID device 200 and the DCS 201. In such examples,communications from the RFID device 200 relative to communications fromthe field device 122 are managed and/or distinguished by the DCS 201based on individual addresses assigned to each of the RFID device 200and the field device 122 (e.g., in a multi-drop configuration). That is,in such examples, the RFID device 200 and the field device 122 aretreated as two separate instruments within the process control system100 connected along the 2-wire connection 218. In some examples, theRFID device 124 may be coupled to a HART compliant field device althoughthe DCS 201 is not implemented using the HART protocol. In suchexamples, the RFID device 200 may not communicate with the DCS 201 butwould communicate with the field device. Although the RFID device 200 inFIG. 2 is shown as being independently connected to the signal wires218, in some examples, the RFID device 200 is coupled to the signalwires 218 via the field device 122 as will be described more fully belowin connection with FIG. 5.

The example HART modem 202 is configured to transmit information fromthe HART field device 122 according to the HART protocol (or any othersuitable communication protocol) to the microcontroller 204 according toa serial communication protocol (e.g., universal serial bus (USB),Ethernet, synchronous serial (e.g., serial peripheral interface (SPI)bus), etc.). Additionally, the example HART modem 202 is configured totransmit information from the microcontroller 204 according to theserial communication protocol to the HART field device 122 and/or to theDCS 201 according to the HART protocol.

The example microcontroller 204 controls the timing and/or scheduling ofdata sent to and/or from the field device 122 and/or the RFID tag 210.In some examples, the data includes requests to poll information (e.g.,process variable values, alarms, etc.) from the field device 122. Inother examples, the data includes commands instructing the field device122 to implement certain functionality (e.g., tuning, calibration,diagnostics, commissioning, etc.). Data received by the microcontroller204 of the illustrated example may be stored temporarily in the RAM 207and/or stored long-term in the non-volatile memory 208. Additionally oralternatively, the data received by the microcontroller 204 may be sentto the RFID processor 212 for subsequent storage in the correspondingRFID onboard memory 214 and/or transmitted to an external RFIDreader/writer 206 via the RFID antenna 216.

As identified by brace 230, communications between the field device 122,the HART modem 202 of the RFID device 200, and the DCS 201 arerelatively slow or low speed because the communications are governed bythe HART protocol, which is limited to about 1200 baud. In contrast, thecommunications between the other elements illustrated in FIG. 2, asidentified by brace 232, are relatively high speed in that they arebased on a high speed serial communication protocol (e.g., SPI bus),which may achieve approximately 115 kbps. Thus, by implementing theexample RFID device 200 in accordance with the teachings disclosedherein, relatively slow HART based communications may be monitoredovertime and cached or stored in the non-volatile memory 208 and/or theRFID onboard memory 214 for subsequent access by plant personnelhandling an RFID reader/writer (e.g., the RFID reader/writer 206 shownin FIG. 2) at a much faster rate via the serial bus communicationprotocol.

In some examples, as identified by brace 222, the communicationsassociated with the field device 122, the HART modem 202, themicrocontroller 204, the non-volatile memory 208 and the random accessmemory 207 (represented in FIG. 2 by solid lines 224) require power fromthe DCS 201 via the signal wires 218 to operate (i.e., these componentsare loop powered). In contrast, as identified by brace 226, thecommunications within the RFID tag 210 (represented by dotted lines 228)and the wireless communication between the RFID antenna 216 and the RFIDreader/writer 206 do not require control system power (e.g., looppower). Rather, the RFID communications in the illustrated example(e.g., those identified by the dotted lines 228) draw power from theRFID reader/writer 206 via inductive or radiative coupling. Thus, notonly can the RFID tag 210 function without loop power, the RFID tag 210can function without a battery supply or charged capacitors (e.g., whichmay be charged based on available loop power) such that data stored inthe RFID onboard memory 214 of the RFID tag 210 is accessible any timethe RFID reader/writer 206 is within range of the antenna 216.Additionally or alternatively, in some examples, the RFID device 200 isprovided with a battery supply and/or capacitor for redundancy or backuppower when control system power is unavailable.

In some examples, the amount of data that can be stored onboard the RFIDtag 210 (e.g., within the RFID onboard memory 214) is relatively limitedbecause it is to be powered by the RFID reader/writer 206. For example,many known passive RFID tags typically have an upper memory threshold of32 kilobytes. However, with RFID technology there is a tradeoff betweenthe amount of memory available and the range over which data stored onthe memory can be accessed wirelessly via an RFID reader/writer. Forexample, using the 32 kilobytes of memory may limit the RFIDcommunication range to around 2 feet, whereas smaller amounts of memory(e.g., 512 bits) can allow ranges exceeding 30 feet (the range may alsodepend upon the antenna design of the RFID tag). In some examples, arange of 2 feet may be acceptable. However, in other examples, where afield device is not readily accessible by plant personnel in the field(e.g., is placed up high, located behind other equipment, beyond safetyboundaries, etc.), the RFID onboard memory 214 of the RFID tag 210corresponding to such a field device may only contain 512 bits of data,which enables a range of approximately 30 feet. Accordingly, the terms“local,” “near,” “nearby,” and related terms associated with thelocation or position of plant personnel and/or an RFID reader/writerrelative to a field device are expressly defined as being within themaximum range of communication between the RFID reader/writer and anRFID device physically coupled to the corresponding field device.

While the memory of the RFID tag 210 (e.g., the RFID onboard memory 214)is relatively limited, the non-volatile memory 208 associated with themicrocontroller 204, in some examples, can be any size (e.g., megabytesor even gigabytes of memory) within the constraints of manufacturingcapabilities. In some examples, the non-volatile memory 208 is removableand replaceable (e.g., like an SD card) to enable the end user to selectthe desired amount of memory. In this manner, additional informationrelated to the field device 122 can be stored that may otherwise beunavailable due to the limited memory space of the field device 122. Forinstance, in some examples, the non-volatile memory 208 storesmaintenance and/or repair information gathered over the entire lifecycleof the field device 122 (or any portion thereof). Such information mayinclude recommended parts lists, photos, model/serial number of thefield device and/or associated parts, maintenance instructions and/orprocedures, as well as a historical archive of the nature and timing ofany device failures and resulting maintenance response (e.g., errorsignals, alerts/alarms, diagnostic test results, part replacements,etc.). In this manner, whenever maintenance technicians are examiningthe field device (e.g., during a routine walk-down, because of a devicefailure, or as part of turnaround planning), they will have immediateand ready access to all relevant information to be able to assess thesituation and/or implement appropriate next steps. Furthermore, in thismanner, the same relevant information is even accessible if the devicehas been removed and relocated from the plant for the purposes of repairand/or more exhaustive diagnostic testing.

Further, as shown in the illustrated example, the communication betweenthe microcontroller 204 and the RFID processor 212 uses loop power suchthat not everything that can be stored in the non-volatile memory 208associated with the microcontroller 204 will be available to the RFIDtag 210 when there is no power. Accordingly, in some examples, a subsetof the data obtained from the field device 122 that is likely to be ofthe most benefit when there is no power is stored directly on the RFIDtag 210 (e.g., in the RFID onboard memory 214) as is described morefully below. Even though it is unlikely that the RFID tag 210 can storeall data gathered from the field device 122 because the amount of memoryrequired exceeds the memory available in the RFID onboard memory 214,caching the data from the non-volatile memory 208 still provides theadvantage of wirelessly accessing the data (via the RFID reader/writer206) at communications speeds much higher than possible if the fielddevice 122 were polled directly, which is subject to the relatively slowcommunication speed of the HART protocol. However, in the illustratedexample, loop power is used to enable the RFID tag 210 to communicatewith the microcontroller 204 and access the non-volatile memory 208.Thus, when the microcontroller 204 and the non-volatile memory 208 areloop powered, the RFID reader/writer 206 may access all of the datastored on the non-volatile memory 208 via the RFID tag 210 regardless ofwhether the data is also stored on the RFID onboard memory 214.

Implementing communications via RFID technology in accordance with theteachings disclosed in connection with FIG. 2 has several advantages.First, RFID transmissions can occur whenever they are desired and plantpersonnel have an RFID reader/writer that is within a suitable range.That is, RFID communications between the RFID tag 210 and the RFIDreader/writer 206 of the illustrated example are not dependent on theprocess control system 100 being in operation and powered up. Incontrast, other known wireless radio transceivers used in processcontrol systems (e.g., based on a ZigBee communication protocol) requirea significant amount of power, which is often scavenged from availableloop power provided to the corresponding field device over time untilcapacitors associated with the transceiver are sufficiently charged topower a signal transmission. Due to the tight power budget frequentlyassociated with the low voltage power source provided to field devices,a delay of up to a minute may be needed to harvest sufficient power totransmit a HART command. Under such constraints, the types (and amounts)of wireless communications possible are significantly limited (e.g., toproviding basic control information such as values for process variable,and/or other key parameters). For example, diagnosing and/or configuringa HART field device can involve well over 1000 HART commands. Atapproximately one HART command per minute, ZigBee based wirelesstransceivers are not practical for such purposes. However, as RFIDtechnology uses no other power than what is provided by an RFIDreader/writer (e.g., in a passive mode), data can be freely communicatedwhenever the RFID reader/writer is within range of the antenna of anRFID tag.

Another advantage of using the RFID tag 210 of the illustrated exampleto enable wireless communications is that such communications can becarried out even if the DCS 201 is shut down, the field device 122 istaken out of service, and/or power is otherwise cut off. Thus, not onlycan the RFID tag 210 communicate with the RFID reader/writer 206 whenthe field device 122 is without power, the same communications are stillavailable even when the field device is taken offsite (e.g., when beingshipped off for repairs) and/or before being installed and commissionedinto a control system. Inasmuch as such communications are made withoutloop power, the corresponding data in such examples is stored onboardthe RFID tag 210 (e.g., in the RFID onboard memory 214). In suchexamples, due to the memory constraints of the RFID tag 210, only thedata that is most likely to be desired when there is no power is storedin the RFID tag 210 (any additional data gathered from the field device122 may be stored in the non-volatile memory 208). In some examples, thedata stored in the RFID tag 210 is associated with the identification(e.g., serial card data), maintenance (e.g., historical records ofrepairs, part replacements, diagnostic tests, etc.), and/orcommissioning and/or configuring (e.g., operational settings and/ortuning parameters) of the field device 122. Storing such information onthe RFID tag 210 is advantageous because the data can be used to improvethe accuracy and speed with which the field device 122 may be repaired(many cases of which involve the field device being unpowered). Forexample, by storing the serial number of the field device 122 on theRFID tag 210 (which, in some examples, is physically attached to thefield device even during shipping for repairs), the field device 122 canbe identified during the shipping process (e.g., when it is crated on atruck) to reduce the potential of the field device 122 becoming lostand/or confused with another device.

Further, in some examples, the maintenance data associated with thefield device 122 stored on the RFID onboard memory 214 of the RFID tag210 may include the date of manufacture, part numbers and/or a partslist (e.g., based on an engineering master (EM) string to reduce memoryrequirements), spare parts recommendations, a specification sheet,images/photos of the field device 122 and/or corresponding parts, and/ormaintenance records (e.g., the date of last maintenance and/orcalibration, the date when the field device 122 was first installed, thedate(s) of diagnostic tests and their results, alert logs, etc.). Inaccordance with the teachings disclosed herein, any or all of the aboveforms of maintenance data may be accessible before the field device 122is coupled to a power supply to facilitate the ordering of parts and/orthe speed at which issues may be assessed and ultimately repaired.

Further, the communication speed of wireless transmissions using theRFID tag 210 is much faster than other known wireless transceivers in aprocess control system. For example, in a wireless HART context, knowntransceivers are typically configured in serial communication with awired HART modem such that the transceiver is limited to the speed ofthe HART protocol associated with the modem (e.g., 1200 baud). Incontrast, the RFID device 200 of FIG. 2 is configured according to ahigh speed serial bus communication protocol that provides much fastercommunications. Thus, while communications that are associated with datastored in the non-volatile memory 208 depend upon loop power, the speedat which data (previously polled from the field device 122) can beaccessed is a significant improvement over polling the field device 122directly.

A related advantage of the RFID device 200 arises from the fact thathigh speed communications are possible while the field device ispowered. Frequently there is a no-touch rule in effect for processcontrol equipment when the process is in operation such that engineersor other maintenance personnel can only access alerts, alarms, ordiagnostic data for a field device via the plant database. While thisinformation is accessible from a control room and/or remote terminal ina maintenance shop, such information is largely unavailable whenpersonnel are local to the field device because known wirelesstransceivers are limited (e.g., by the speed/frequency ofcommunications, as described above) and establishing a hardwiredconnection to a field device may require unscrewing a terminal cap(which may violate a plant safety policy) and/or taking the field deviceout of service, thereby disrupting operations of the plant. However,with the example RFID device 200, the high communication speeds and thewireless nature of the communications overcomes these obstacles forpersonnel with a handheld RFID reader/writer (e.g., the RFIDreader/writer 206) at or near the location of the field device 122.

Additionally, in some examples, the RFID tag 210 may store theparticular asset tag for the field device 122 and/or other data relatedto commissioning and/or configuring the field device 122. Generally,when a field device is commissioned or configured, a field technicianexecutes a series of tests to verify the functionality of the fielddevice and subsequently configures and calibrates the field device bystoring operational settings in the field device for installation intothe process plant. In some examples, such operational settings toconfigure and calibrate the field device are stored within the RFIDonboard memory 214 of the RFID tag 210. In such examples, should thefield device fail or otherwise need replacing, plant personnel canquickly retrieve the operational settings from the failed device (viathe RFID reader/writer 206) and load them on another RFID tag 210corresponding to a replacement field device. In other examples, the RFIDdevice 200 may be taken from the removed field device and coupled to thereplacement field device to provide the stored operational settingsdirectly to the new replacement device. By implementing either of theabove examples, the time efficiency for switch outs of replacement fielddevices may be significantly improved. That is, the typically manualprocess of validating and/or populating variables and other parametersto commission and configure the field device 122 can be automated tosignificantly reduce labor costs and improve accuracy by reducingwritten errors. Furthermore, in some examples, a field device (e.g., thefield device 122) may be temporarily replaced or removed from servicewhile it is repaired before being re-installed within the processsystem. In some such examples, if any data associated with the fielddevice 122 changes after being repaired, the memory in the RFID tag 210may be updated (while the field device 122 is powered) such that the newinformation is accessible (via the RFID reader/writer 206) before thefield device 122 is re-installed and re-commissioned in the processcontrol system 100.

FIG. 3 illustrates another example RFID device 300 that may be used toimplement the example RFID device 124 of FIG. 1. As with FIG. 2, theRFID device 300 of FIG. 3 is shown connected to the field device 122 ofthe process control system 100 of FIG. 1 (the remainder of which isrepresented by the DCS block 201). In the illustrated example, the RFIDdevice 300 includes a power manager 302, a capacitor 304, and an RFIDtag 306 that comprises a main RFID processor 308 and an RFID onboardmemory 310, and an RFID antenna 312. In some examples, the RFIDprocessor 308, the RFID onboard memory 310, and the RFID antenna 312 areall incorporated onto a single integrated circuit (IC).

Similar to the field device 122 shown in FIG. 2, the field device 122 inthe illustrated example of FIG. 3 is operatively coupled to the DCS 201via the signal wires 218 (represented by the two solid lines) throughwhich control signals are transmitted and power is provided to the fielddevice 122. Further, in the illustrated example of FIG. 3, the RFIDdevice 300 is linked to the signal wires 218 such that the field device122 is operatively coupled to the RFID device 300 to enable the RFIDdevice 300 to receive data sent from the field device 122. Additionally,the coupling of the example RFID device 300 to the signal wires 218enables the RFID device 300 to draw off power provided to the fielddevice 122. More particularly, as shown in FIG. 3, the RFID device 300is coupled to the signal wires 218 via the field device. In someexamples, such as when the signal wires 218 corresponds to a 24 voltdigital bus (e.g., network powered) to implement the Foundation Fieldbusprotocol, the RFID device 300 is connected to the signal wires 218 inparallel with the field device 122 (similar to the connection shown forthe RFID device 200 of FIG. 2). In other examples, such as when thesignal wires 218 is an analog 4-20 mA current loop (e.g., loop power) toimplement the HART protocol, the RFID device 300 is connected to thesignal wires 218 in series with the field device 122.

In the illustrated example of FIG. 3, the RFID tag 306 operates in asemi-passive mode such that the RFID processor 308 and the RFID onboardmemory 310 are powered independently of the RFID reader/writer 206. Inparticular, in some examples, the RFID processor 308 and the RFIDonboard memory 310 are powered via the field device 122 (e.g., via thecontrol system power provided to the field device 122). As representedby the solid lines 314 in the illustrated example of FIG. 3, thecommunications associated with the field device 122, the power manager302, the capacitor 304, the RFID processor 308, and the RFID onboardmemory 310 rely on control system power. Thus, unlike the communicationsassociated with the RFID processor 212 and the RFID onboard memory 214of the RFID tag 210 of FIG. 2 (represented by the dotted lines 228) thatare powered by the RFID reader/writer 206, the RFID processor 308 andthe RFID onboard memory 310 of FIG. 3 are control system powered.However, the communications of the RFID antennas 216, 312 in both FIGS.2 and 3 are powered by the RFID reader/writer 206 (as represented by thecorresponding dotted lines 228, 316).

As described above, the RFID onboard memory 214 of the RFID tag 210 ofFIG. 2 is relatively limited because the memory relies on the RFIDreader/writer 206. In contrast, the RFID onboard memory 310 of the RFIDtag 306 in the illustrated example of FIG. 3 is not so limited by powerconstraints because the RFID onboard memory 310 (along with the RFIDprocessor 308) relies on control system power from the DCS 201.Accordingly, in some examples, the RFID onboard memory 310 may store upto any suitable amount of data (e.g., megabytes or even gigabytes ofdata). In this manner, more information can be stored onboard the RFIDtag 306 such that a separate nonvolatile memory (such as thenon-volatile memory 208 of the RFID device 200 of FIG. 2) may beunnecessary to store the data received from and/or associated with thefield device 122. However, in some examples, the RFID onboard memory 310may nevertheless be somewhat limited to enable access to informationstored thereon if power is lost or otherwise becomes unavailable bypowering the memory via the RFID reader/writer 206 (e.g., operating in apassive mode) at a short range (e.g., within one foot). In some suchexamples, the memory size of the RFID onboard memory 310 may be up to 1gigabyte. Further, in some examples, due to the typically powered natureof the RFID onboard memory 310, the memory may be implemented usinghigher capacity memory, such as for example, magnetoresistive randomaccess memory (MRAM), which has several features that may be desirablein a control system environment. For example, although MRAM uses morepower, MRAM may be desirable in that it is radiation resistant, has ahigh number of writes, has relatively long memory storage without arefresh, and has relatively long memory storage at elevatedtemperatures.

With the RFID processor 308 and the RFID onboard memory 310 powered viathe field device 122 as described above, the RFID antenna 312 can beimproved (e.g., optimized) for communications because all the powerreceived via the EMF of the RFID reader/writer 206 may be devoted to thecommunications. In particular, the RFID antenna 312 can be structuredmore for omni-directional communications (rather than directional forpurposes of power conversion) that can read longer ranges than possibleusing a passive RFID tag (e.g., as shown in the illustrated example ofFIG. 2). Although the RFID tag 306 of FIG. 3 is configured to functionin a semi-passive mode with the RFID processor 308 and RFID onboardmemory 310 powered via the signal wires 218, in some examples, the RFIDtag 306 may still function in a passive mode when no power is provided(e.g., when there is a shut down, the field device is taken out ofservice, when the field device is first uncrated, etc.) by receivingpower from the RFID reader/writer 206 via the RFID antenna 312. Thus,the RFID tag 310 is capable of communicating over a long range when thefield device 122 is powered (thereby providing power to the RFID device300) but also communicating over a short range when the field device 122is not powered as illustrated by the two RFID reader/writers 206illustrated in FIG. 3.

As the RFID onboard memory 310 of FIG. 3 uses more power than the RFIDonboard memory 214 of FIG. 2, the maximum read range for the RFID device300 of FIG. 3 when operating without power (e.g., in a passive mode) isless than the read range for the RFID device 200 of FIG. 2. For example,as described above, the RFID device 200 of FIG. 2 has a read range of upto about 30 feet regardless of whether the field device is powered. Incontrast, while the RFID device 300 of FIG. 3 has a read range of up toabout 90 feet when powered by the field device 122, if there is nopower, the resulting read range may be limited to within a foot of theRFID antenna 312 because the tag 306 includes a higher capacity memorythat uses more power than the RFID onboard memory 214 described inconnection with FIG. 2 above. Thus, the example RFID devices 200, 300shown and described in connection with FIGS. 2 and 3 are representativeof different trade-offs made with respect to wireless communications.The example RFID device 200 of FIG. 2 is capable of maintainingrelatively long read ranges (e.g., up to 30 feet) even when there is nopower available, but the tradeoff for maintaining this communicationrange is that the RFID onboard memory 214 is relatively limited instorage capacity. However, as described above, the limited onboardmemory of the example RFID device 200 of FIG. 2 is somewhat mitigated bythe separate non-volatile memory 208 that may be available when power isavailable. On the other hand, the RFID device 300 of FIG. 3 is capableof significantly longer read ranges (e.g., up to 90 feet) along with anincreased onboard memory capacity, but the tradeoff is that the extendedread range is dependent upon control system power being provided to theRFID device 300. Further, if no control system power is available, theincreased memory capacity of the example RFID device 300 of FIG. 3 isstill available but is limited to circumstances when the RFIDreader/writer 206 is within approximately one foot of the device.

Aside from the differences in powering of the RFID tag 210 of FIG. 2 andthe RFID tag 306 of FIG. 3 and the resulting differences in read rangesand memory capacities, the RFID devices 200, 300 shown in each of FIGS.2 and 3 differ in other ways as well. In particular, unlike the exampleRFID device 200 of FIG. 2, the example RFID device 300 of FIG. 3 doesnot include the HART modem 202. Instead of having a HART modem 202 as inthe RFID device 200 of FIG. 2 to communicate HART data (or other data ifthe modem corresponds to a different protocol), the RFID device 300 ofFIG. 3 may store any type of data received from and/or pertaining to anytype of field device 122. As such, the RFID device 300 of FIG. 3 has theadvantage of being substantially universal in its application. Thus, asshown in FIG. 3, the field device 122 is not designated as a HART fielddevice (or other specific protocol) as shown in FIG. 2. While the RFIDdevice 300 has the advantage of receiving data from and/or pertaining toany type of field device, the RFID device 200 of FIG. 2 has theadvantage of being able to provide protocol specific communications ofdata back to the field device 122 and/or the DCS 201, thereby enabling,for example, communications with the DCS 201 and/or the commissioningand/or configuration of a field device when put into service (e.g.,after being repaired).

Further, in the illustrated example of FIG. 3, the RFID device 300 isprovided with the power manager 302 that serves as a power supply toscavenge power from the field device (e.g., control system powerprovided by the DCS 201) and provide power to the RFID tag 306 (e.g.,for semi-passive operation). In some examples, the power manager 302 maybe associated with the capacitor 304 to store energy harvested from thecontrol system power. In such examples, power may be available to theRFID tag 306 if the control system power is intermittently unavailable(e.g., when the power requirements of the field device 122 are using allthe control system power). In some examples, the capacitor 304 is asupercapacitor. As the power manager 302 draws power from the fielddevice 122 to charge the capacitor 304, the power manager 302 may absorbcontrol signals communicated along the signal wires 218. Accordingly, insome examples, the power manger 302 includes a signal conditioner toenable power to be tapped off of the control system without disruptingsignals communicated over the control system.

While example manners of implementing the RFID device 124 of FIG. 1 areillustrated in FIGS. 2 and 3, one or more of the elements, processesand/or devices illustrated in FIGS. 2 and/or 3 may be combined, divided,re-arranged, omitted, eliminated and/or implemented in any other way.For example, the RFID device 200 of FIG. 2 may be implemented using theRFID tag 306 described in FIG. 3 and/or the RFID device 300 of FIG. 3may be implemented using the RFID tag 210 of FIG. 2 based on anysuitable power arrangement. That is, in some examples, either of theRFID tags 210, 306 may be configured to operate in a fully-passive mode.In some examples, either of the RFID tags may be configured such thatthe corresponding RFID processor 212, 308 and RFID onboard memory 214,310 of FIG. 2 may be control system powered while the RFID antenna 216,312 is powered via the RFID reader/writer 206. In other examples, theRFID antenna 216, 312 may be control system powered while the RFIDprocessor 212, 308 and the RFID onboard memory 214, 310 rely on powerfrom the RFID reader/writer 206. Likewise, in some examples, each of theRFID devices 200, 300 are provided with a battery power or capacitor.Additionally, either of the RFID device tags 210, 306 may be adapted tobe implemented in a fully active mode for longer communication rangesthat may be broadcast by the corresponding antenna 216, 312.Furthermore, in some examples, the RFID device 300 of FIG. 3 may includea separate non-volatile memory similar to that described in FIG. 2 tosupplement the RFID onboard memory 310. Further, the example HART modem202, the example microcontroller 204, the example RAM 207, the examplenon-volatile memory 208, and the example main RFID processor 212, theexample RFID onboard memory 214, and the example RFID antenna 216 of theexample RFID tag 210, the example power manager 302, the examplecapacitor 304, and the example RFID processor 308, the example RFIDonboard memory 310, and/or the example RFID antenna 312 of the exampleRFID tag 306, and/or, more generally, the example RFID devices 200, 300of FIGS. 2 and/or 3 may be implemented by hardware, software, firmwareand/or any combination of hardware, software and/or firmware. Thus, forexample, any of the example HART modem 202, the example microcontroller204, the example RAM 207, the example non-volatile memory 208, theexample main RFID processor 212, the example RFID onboard memory 214,and the example RFID antenna 216 of the example RFID tag 210, theexample power manager 302, the example capacitor 304, and the exampleRFID processor 308, the example RFID onboard memory 310, and/or theexample RFID antenna 312 of the example RFID tag 306, and/or, moregenerally, the example RFID devices 200, 300 could be implemented by oneor more analog or digital circuit(s), logic circuits, programmableprocessor(s), application specific integrated circuit(s) (ASIC(s)),programmable logic device(s) (PLD(s)) and/or field programmable logicdevice(s) (FPLD(s)). When reading any of the apparatus or system claimsof this patent to cover a purely software and/or firmwareimplementation, at least one of the example, example HART modem 202, theexample microcontroller 204, the example RAM 207, the examplenon-volatile memory 208, and/or the example main RFID processor 212, theexample RFID onboard memory 214, and/or the example RFID antenna 216 ofthe example RFID tag 210, the example power manager 302, the examplecapacitor 304, and the example RFID processor 308, the example RFIDonboard memory 310, and/or the example RFID antenna 312 of the exampleRFID tag 306 is/are hereby expressly defined to include a tangiblecomputer readable storage device or storage disk such as a memory, adigital versatile disk (DVD), a compact disk (CD), a Blu-ray disk, etc.storing the software and/or firmware. Further still, the example RFIDdevices 200, 300 of FIGS. 1, 2, and/or 3 may include one or moreelements, processes and/or devices in addition to, or instead of, thoseillustrated in FIGS. 1, 2, and/or 3 and/or may include more than one ofany or all of the illustrated elements, processes and devices.

Another aspect of the teachings disclosed herein is the use ofasymmetric cryptography to protect any or all of the data or recordsstored on the RFID devices 124, 200, 300. As depicted in FIG. 4,asymmetric cryptography or encryption refers to a cryptographic systemutilizing two separate cryptographic keys that asymmetrically control orprotect the storage, access, and/or retrieval of data and/or records inthe RFID devices 124, 200, 300 associated with a field device 122. Forinstance, in some examples, an encryption key 402 serves to lock (e.g.,encrypt) data written to the RFID device memory. In some such examples,a separate decryption key 404 serves to unlock or read (e.g., decrypt)the data records. Further, in some examples, neither the encryption key402 nor the decryption key 404 can perform both the encryption anddecryption functions by itself That is, the encryption key 402 cannot beused to access (e.g., read) the data and the decryption key 404 cannotbe used to alter, remove, or overwrite the data.

Using asymmetric cryptography in this manner, manufacturers can providemanufacturer certified information associated with the field device 122(e.g., serial card data, certified part information, etc.) withoutcompromising the security of such certification, for example, from thirdparty entities repairing and/or replacing components of the field device122 with non-certified replicated parts and/or correspondingnon-certified information. To do so, in some examples, the manufactureruses the encryption key 402 to initially encrypt information at the timeof manufacture. In some examples, encryption is accomplished via an RFIDreader/writer maintained by the manufacturer that includes theencryption key 402 (e.g., the manufacturer RFID reader/writer 406). Insome examples, decryption is accomplished via a separate RFIDreader/writer maintained by a technician or other end user that includesthe decryption key 404 (e.g., the field technician RFID reader/writer408). Additionally or alternatively, in some examples, a manufacturermay provide the encryption key 402 directly with a newly manufacturedfield device 122 to encrypt the relevant information. Further, in somesuch examples, the encryption key 402 associated directly with the fielddevice 122 enables data generated by the field device 122 duringoperation to also be secured through encryption. In this manner,manufacturers can provide relevant data to be stored in the non-volatilememory 208 of the RFID device 200 (or in the onboard memory 310 of theRFID device 300) that is protected (e.g., encrypted) to reduce thepotential for such information being altered, removed, corrupted, orconfused with any non-secured (e.g., unencrypted) information.

As a specific example, serial card data or certified part informationmay be encrypted and stored with the non-volatile memory of the RFIDdevice 200 of FIG. 2 by a field device manufacturer (e.g., via amanufacturer RFID reader/writer 406 or based on the encryption key 402within the field device 122 itself) to create secure, certified dataspecific to the field device 122 accessible throughout the lifecycle ofthe device without concern for the data being changed or mistaken forother information to ensure tracking and maintenance information isprotected. Additionally or alternatively, in some examples the fielddevice 122 may encrypt (e.g., via the encryption key 402) operationaldata (e.g. failure events or alerts) to provide secure operationalrecords for later diagnostic analysis. In some such examples, thedecryption key 404 may be provided or published to enable maintenancetechnicians or other users to readily access parts information ormaintenance data (e.g. photographs, instruction manuals) via a fieldtechnician RFID reader/writer 408 (e.g., associated with the decryptionkey 404) but not enable the technicians or other third party entities toalter or remove (inadvertently or otherwise) the secured information. Inthis manner, technicians have ready access to helpful information withless concern for errant data records and/or out of date informationrelated to the field device 122 and without compromising security of therecords created by the manufacturer.

As shown in the illustrated example, the difference between themanufacturer RFID reader/writer 406 and the field technician RFIDreader/writer 408 is the cryptographic key 402, 404 with which each RFIDreader/writer 406, 408 is associated. That is, each of the RFIDreader/writer 406, 408 may be a same or similar RFID reader/writer, eachof which is supplied with either the encryption key 402 or thedecryption key 404. In some examples, the encryption key 402 or thedecryption key 404 is downloaded to the corresponding RFID reader/writer406, 408 via a USB dongle or USB connection with a computer that has thecorresponding cryptographic key 402, 404. In some examples, theencryption key 402 or the decryption key 404 is provided to thecorresponding RFID reader/writer 406, 408 manually by entering therelevant information via a user interface (e.g., keypad) on the RFIDreader/writer 406, 408.

Additionally or alternatively, in some examples, the encryption key 402or the decryption key 404 is provided to the corresponding RFIDreader/writer 406, 408 via a manufacturer provided key fob,authentication card, or security token. In some such examples, the keyfob functions in connection with the corresponding RFID reader/writer406, 408 based on far field communications. That is, when a key fobassociated with the encryption key 402 is within range for far fieldcommunications (e.g., less than one foot), the capability of themanufacturer RFID reader/writer 406 to encrypt data is activated whereaswhen the key fob is out of range, the encryption functionality isunavailable. Similarly, when a key fob associated with the decryptionkey 404 is within range, the decryption functionality is available tothe field technician RFID reader/writer 408 but becomes unavailable oncethe key fob is taken out of range. In some situations, the field device122 may not be directly associated with the encryption key 402 and themanufacturer RFID reader/writer 406 may not be available for encryptionwhen the manufacturer desires (e.g., when a manufacturer representativeor other authorized personnel is visiting a client with previouslypurchased field devices). Accordingly, in some examples, themanufacturer authorized personnel is provided with the key fobassociated with the encryption key 402 that, once authenticated, wouldenable the user to add desired encrypted information (e.g., an updatedcertified parts list) without a designated encryption RFID reader/writer(e.g., the manufacturer RFID reader/writer 406 maintained at themanufacturing site of the field device 122). In some such examples, thekey fob may be used in conjunction with the field technicianreader/writer 408 to encrypt the desired information. Further, in someexamples, the key fob and/or the RFID reader/writer 408 can communicatewith multiple RFID devices 124, 200, 300 at one time (that are withinthe RFID signal range) to update each corresponding field device asappropriate.

FIG. 5 illustrates a particular implementation of the example RFIDdevices of FIGS. 1, 2, and/or 3 to be physically and operatively coupledto an example field device 500 comprising an actuator 502 and a valvecontroller 504 coupled to a valve 506. More particularly, in someexamples, as shown in FIG. 5, the RFID device 124 (e.g., the RFIDdevices 200, 300 of FIGS. 2 and/or 3) is physically coupled to the fielddevice 500 by fastening threads 508 of the RFID device 124 to the valvecontroller 504. In some examples, the threads 508 conform to standardpiping threads. Additionally, in some examples, the RFID device 124 isoperatively coupled to the field device 500 by connecting wires 510 ofthe RFID device 124 to the valve controller 504 within a terminal box512 of the valve controller 504. In this manner, the RFID device 124 hasaccess to the control system power provided from a control room to thefield device from which the RFID device 124 can power its internalcomponents as described above. Many existing field devices haveauxiliary input terminals within the terminal box to which the wires 510may be connected such that the RFID device 124 can be retrofitted tomany existing field devices. In other examples, the RFID device 124 isincorporated directly into a field device rather than being a separatedevice that is coupled thereto.

In some examples, the RFID antenna 216, 312 of the corresponding RFIDdevice 200, 300 shown in FIGS. 2 and 3 is located at an end 514 of theRFID device 124 opposite the threads 508. In some examples, the threads508 can be used in conjunction with standard pipe fittings (e.g., anelbow) to orient the RFID antenna 216, 312 in any desired directionindependent of the valve controller 504. In other examples, the RFIDantenna 216, 312 may be omni-directional such that orientation of theRFID device is less significant.

As shown in the illustrated example of FIG. 5, by physically connectingand operatively wiring the RFID device 124 to the field device 500, ahazardous area rating can be achieved that enables wirelesscommunications to a nearby RFID reader/writer (e.g., the RFIDreader/writer 206). Furthermore, the physical attachment of the RFIDdevice 124 to the field device 500 enables the RFID tag 210, 306 to bepermanently associated with the field device 500 (i.e., for as long asthe RFID device remains fastened to the field device 500) even when thefield device 500 is taken out of service, removed to a new location,and/or isolated from the rest of the process control system (e.g., formaintenance and/or repair).

Flowcharts representative of example methods for implementing the RFIDdevices 124, 200, 300 of FIGS. 1, 2, and/or 3 are shown in FIGS. 6-10.In some examples, the methods may be implemented as a program forexecution by a processor such as the processor 1112 shown in the exampleprocessor platform 1100 discussed below in connection with FIG. 11. Theprogram may be embodied in software stored on a tangible computerreadable storage medium such as a CD-ROM, a floppy disk, a hard drive, adigital versatile disk (DVD), a Blu-ray disk, or a memory associatedwith the processor 1112, but the entire program and/or parts thereofcould alternatively be executed by a device other than the processor1112 and/or embodied in firmware or dedicated hardware. Further,although the example program is described with reference to theflowcharts illustrated in FIGS. 6-10, many other methods of implementingthe example RFID devices 124, 200, 300 may alternatively be used. Forexample, the order of execution of the blocks may be changed, and/orsome of the blocks described may be changed, eliminated, or combined.

As mentioned above, the example methods of FIGS. 6-10 may be implementedusing coded instructions (e.g., computer and/or machine readableinstructions) stored on a tangible computer readable storage medium suchas a hard disk drive, a flash memory, a read-only memory (ROM), acompact disk (CD), a digital versatile disk (DVD), a cache, arandom-access memory (RAM) and/or any other storage device or storagedisk in which information is stored for any duration (e.g., for extendedtime periods, permanently, for brief instances, for temporarilybuffering, and/or for caching of the information). As used herein, theterm tangible computer readable storage medium is expressly defined toinclude any type of computer readable storage device and/or storage diskand to exclude propagating signals and to exclude transmission media. Asused herein, “tangible computer readable storage medium” and “tangiblemachine readable storage medium” are used interchangeably. Additionallyor alternatively, the example methods of FIGS. 6-10 may be implementedusing coded instructions (e.g., computer and/or machine readableinstructions) stored on a non-transitory computer and/or machinereadable medium such as a hard disk drive, a flash memory, a read-onlymemory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage device or storage disk inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, for brief instances, for temporarily buffering,and/or for caching of the information). As used herein, the termnon-transitory computer readable medium is expressly defined to includeany type of computer readable device or disk and to exclude propagatingsignals and to exclude transmission media. As used herein, when thephrase “at least” is used as the transition term in a preamble of aclaim, it is open-ended in the same manner as the term “comprising” isopen ended.

FIG. 6 is a flowchart representative of an example method forimplementing the example RFID devices 124, 200 of FIGS. 1, and/or 2 towirelessly communicate data from a field device to a local RFIDreader/writer. In particular, the example method of FIG. 6 begins atblock 600 with the microcontroller 204 monitoring communicationsassociated with a field device (e.g., the field device 122). In someexamples, the microcontroller 204 monitors communications by requestingand/or to interrogating the field device 122 for data via the examplemodem 202. In other examples, the microcontroller 204 passively receivesdata (e.g., device alerts) from the field device 122 whenever they aretransmitted (e.g., when in burst mode). Additionally or alternatively,in some examples, the microcontroller 204 may passively receive plantalerts or other data sent to the field device 122 from the DCS 201.Thus, in some examples, the microcontroller 204 is configured to monitorall bus traffic on the signal wires 218 to be collected and stored.Furthermore, because the monitoring is accomplished through the HARTmodem 202, there is no need to be directly linked to the processor ofthe field device. As a result, the RFID device 124 can be coupled to anytype of field device (e.g., positioner, transmitter, etc.) without theneed for any special configurations for the particular device.

At block 602 of the example method, the non-volatile memory 208 of theRFID device 200 stores the collected data. One advantage of storing thedata in the non-volatile memory 208 is that, once stored, the data isaccessible at much faster communication speeds because the transmissionsof the data are no longer limited by the relatively slow HARTcommunication protocol (e.g., through the modem 202). This is especiallya concern when plant personnel located in the field near a field devicedesire a large amount of data. For example, plant personnel may desireto access the historical maintenance records over the life of aparticular field device to trend the error signals of the device overtime. Typically, a technician in the field local to the field devicewould physically clip on to the device (e.g., opening the terminal cap)and request such information from a remote central control facilitywhere the maintenance records were stored because the amount of data(e.g., all error signals and/or alerts generated over the life of thefield device) would exceed the limited memory capacities of the fielddevice. Furthermore, retrieving the data from a remote facility wouldtypically be accomplished over the relatively slow communicationprotocol for the control system. As a result, the retrieval of such datacan be inefficient and impractical. However, if the data is stored orbuffered in advance (e.g., over time) in the non-volatile memory 208 asdisclosed herein, the subsequent retrieval of such information can beperformed relatively quickly based on the high speed communicationspossible between the non-volatile memory 208 and the RFID reader/writer206. Furthermore, the non-volatile memory can be of any suitable size tostore and/or archive any desired information (including information nottypically stored locally at the field device such as the maintenancerecords described above). Another advantage of storing the data on thenon-volatile memory 208 for retrieval via the RFID reader/writer 206 isthat such retrieval is wireless and, therefore, does not requireremoving the terminal cap of the field device 122. In some examples, thefield device is associated with an encryption key (e.g., the encryptionkey 402 of FIG. 4) such that the data stored in the non-volatile memoryis secured and accessible only with a corresponding decryption key(e.g., the decryption key 404 of FIG. 4).

At block 604, the example RFID onboard memory 214 stores a subset of thedata. Although the non-volatile memory 208 can be of any suitable size,the amount of memory available within the RFID tag 210 is relativelylimited such that only some of the data retrieved from the field device122 may be stored within the RFID onboard memory 214. Accordingly, insome examples, the subset of the data includes information associatedwith the identification, maintenance, and/or commissioning of the fielddevice 122 as described above.

At block 606, the example RFID processor 212 wirelessly transmits thedata to an RFID reader/writer (e.g., the example RFID reader/writer 206)located near (e.g., within transmission range) the field device 122. Insome examples, the transmitted data corresponds to the subset of thedata stored on the RFID onboard memory 214. Additionally oralternatively, in some examples, the transmitted data corresponds to thedata stored in the non-volatile memory 208. In some examples, where thedata was encrypted, the RFID reader/writer is associated with thedecryption key to enable access of the data. In the illustrated example,block 600 involves loop power because the RFID device 200 is connectedinto the loop associated with the field device 122 and the field device122 can only provide data when it is receiving such power. Additionally,blocks 602 and 604 involve a power source (e.g., control system powerand/or battery power) to enable the microcontroller 204 to write thecollected data to the non-volatile memory 208 (block 602) and to providethe subset of the data to the RFID processor 212 to be written to theRFID onboard memory 214 (block 604). However, block 606 of the exampleprogram may be implemented with or without control system power (orbattery power or other power source (e.g., solar power)) because theRFID tag 210 is powered by the electromagnetic force generated by thenearby RFID reader/writer.

FIG. 7 is a flowchart representative of an example method similar to theexample method of FIG. 6 for implementing the example RFID devices 124,300 of FIGS. 1 and/or 3 to wirelessly communicate data from a fielddevice to a local RFID reader/writer. In particular, the example methodof FIG. 7 begins at block 700 with the RFID processor 308 receiving datafrom a field device (e.g., the field device 122). At block 702 of theexample method, the RFID onboard memory 310 of the RFID device 300stores the data. As described above, the RFID onboard memory 310 of theexample RFID device 300 of FIG. 3 may have significantly higher storagecapacity than the onboard memory of the RFID device 200 of FIG. 2because the RFID onboard memory 310 is powered by the field device(e.g., via control system power). Accordingly, in some examples, thedata received from the field device is stored directly on to the RFIDtag 306 rather than in a separate non-volatile memory as described abovein connection with FIG. 2. In this manner, any data associated with thefield device may be immediately available to an RFID reader that is nearthe field device (e.g., within the communication range of the RFID tag306). In some examples, the field device is associated with anencryption key (e.g., the encryption key 402 of FIG. 4) such that thedata stored in the RFID onboard memory 310 is secured and accessibleonly with a corresponding decryption key (e.g., the decryption key 404of FIG. 4).

At block 704, the example RFID processor 308 wirelessly transmits thedata to an RFID reader/writer (e.g., the example RFID reader/writer 206)located near (e.g., within transmission range) the field device 122. Insome examples, the transmission range associated with the RFID device300 of FIG. 3 is significantly greater than the range associated withthe RFID device 200 of FIG. 2 because the RFID processor 308 and RFIDonboard memory 310 use control system power to allow the RFID antenna312 to be focused on communications. Not only do such examples enablelonger communication ranges, the RFID antenna 312 may beomni-directional. In some examples, where the data was encrypted, theRFID reader/writer is associated with the decryption key to enableaccess of the data.

FIG. 8 is a flowchart representative of an example method forimplementing the example RFID devices 124, 200, 300 of FIGS. 1, 2,and/or 3 to provide data requested locally via an RFID reader/writer. Inparticular, the example method of FIG. 8 begins at block 800 with theexample RFID processor 212 receiving a request for data from an RFIDreader/writer (e.g., the example RFID reader/writer 206 via the exampleRFID antenna 216, 312). At block 802, the example RFID processor 212,308 communicates the data to the example RFID reader/writer 206 via theexample RFID antenna 216, 312. In some examples, the data corresponds todata cached in the onboard memory 214 of the example RFID device 200 ofFIG. 2 previously provided from the non-volatile memory 208 associatedwith the microcontroller 204. In some examples, where the RFID device300 of FIG. 3 is used, the data is stored directly on the RFID onboardmemory 310 and communicated from there independent of a separatenon-volatile memory. In some examples, the data corresponds to datastored in the non-volatile memory 208 of the example RFID device 200. Insome examples, the communication of the data is based on a fully passiveimplementation of RFID technology and, therefore, does not need controlsystem power because the RFID tag is powered via an EMF of the RFIDreader/writer. In other examples, the RFID device (e.g., as described inFIG. 3) is control system powered. Once the example RFID processor 212,308 communicates the data to the example RFID reader/writer 206 theexample RFID tag 210, 306 is ready to process another request from theRFID reader/writer 206 and the example method of FIG. 8 ends.

FIG. 9 is a flowchart representative of an example method forimplementing the example RFID devices 124, 200, 300 of FIGS. 1, 2,and/or 3 to provide data to the RFID devices 124, 200, 300 associatedwith a field device generated locally via an RFID reader/writer. Inparticular, the example method of FIG. 9 begins at block 900 where theexample RFID tag 210 (via the RFID antenna 216) or the example RFID tag306 (via the RFID antenna 312) receives data associated with a fielddevice (e.g., the field device 122) from an RFID reader/writer (e.g.,the example RFID reader/writer 206). In some examples, the datacorresponds to information relating to the identification and/ormaintenance of the field device such as, for example, serial cardinformation, an asset tag, a specification sheet, an instruction manual,a parts lists and/or associated part numbers, photos/images of the fielddevice 122, etc. In some examples, the data corresponds to new and/oradditional maintenance information corresponding to the field device 122that was previously unavailable (e.g., an updated recommended partslist). In some examples, the RFID reader/writer 206 is associated withan encryption key (e.g., the encryption key 402 of FIG. 4) such that thedata is secured and subsequently accessible only with a correspondingdecryption key (e.g., the decryption key 404 of FIG. 4). At block 902the example RFID processor 212, 308 stores the data in the onboardmemory 214, 310 of the RFID tag 210, 306. In some examples, as with theRFID device 200 of FIG. 2, the communication of the data from the RFIDreader/writer 206 to the onboard memory 214 of the RFID tag 210 isaccomplished without control system power provided to the field deviceand/or the RFID device 200. In other examples, as with the RFID device300 of FIG. 3, the onboard memory 310 and the processor 308 are controlsystem powered. At block 904, the example microcontroller 204 of theexample RFID device 200 writes the data to the example non-volatilememory 208. In some examples, where the data is updated information, themicrocontroller 204 overwrites previously stored information. Withrespect to the RFID device 200 of FIG. 2, block 902 may be omitted asdata is passed through the RFID tag 210 and written directly to thenon-volatile memory 208 without storing the data in the onboard memory214. With respect to the RFID device 300 of FIG. 3, block 904 may beomitted as data is directly written to the RFID onboard memory 310. Atblock 906 the example RFID tag 210, 306 determines whether there is moredata to be received from the RFID reader/writer. If the example RFID tag210, 306 determines there is more data, control returns to block 900. Ifthe example RFID tag 210, 306 determines there is not more data to bereceived, the example method of FIG. 9 ends.

FIG. 10 is a flowchart representative of an example method of replacinga first field device (e.g., the field device 122 of FIG. 1) in a processcontrol system (e.g., the example process control system 100 of FIG. 1)with a second replacement field device using the example RFID devices124, 200 of FIGS. 1, and/or 2 to automatically configure the secondreplacement field device. The example method begins at block 1000 byretrieving operational settings data stored on an RFID device (e.g., theRFID device 200 of FIG. 2) associated with the first field device (i.e.,the field device 122 to be removed). In some examples, the operationalsettings data corresponds to parameters and/or other inputs used in thecommissioning and/or configuration of the field device 122. In someexamples, the operational settings data is retrieved by requesting thedata from the RFID device 200 via an RFID reader/writer (e.g., the RFIDreader/writer 206) as described above. In other examples, theoperational settings data is retrieved by removing (e.g., disconnecting)the RFID device 200 from the field device 122.

At block 1002 of the example method of FIG. 10 the first field device(e.g., the field device 122) in the process control system 100 isreplaced with a second replacement field device. At block 1004 theoperational settings data from the first field device is provided to thesecond replacement field device. In some examples, where the operationalsettings data was retrieved via an RFID reader/writer 206 (block 1000),the operational settings data is wirelessly transmitted to a second RFIDdevice 200 coupled to the second replacement field device. In otherexamples, where the RFID device 200 of the first field device 122 isremoved to retrieve the operational settings data (block 1000), theoperational settings data is provided by connecting the RFID device 200to the second replacement field device. In either example, the secondreplacement field device has direct access to the operational settingsdata. Accordingly, at block 1006, the second replacement field device isconfigured based on the operational settings data. Because theoperational settings data originally stored in connection with the firstfield device 122 is transferred to the second replacement device, theconfiguration and commissioning of the second replacement device can beaccomplished substantially automatically without the need for plantpersonnel to enter individual parameter values as would be otherwiserequired. Once the second replacement field device is configured (block1006), the example method of FIG. 10 ends.

FIG. 11 is a block diagram of an example processor platform 1100 capableof executing instructions to perform the methods of FIGS. 6-10 toimplement the RFID devices 124, 200, 300 of FIGS. 1, 2, and/or 3. Theprocessor platform 1100 can be, for example, any type of computingdevice.

The processor platform 1100 of the illustrated example includes aprocessor 1112. The processor 1112 of the illustrated example ishardware. For example, the processor 1112 can be implemented by one ormore integrated circuits, logic circuits, microprocessors or controllersfrom any desired family or manufacturer.

The processor 1112 of the illustrated example includes a local memory1113 (e.g., a cache). The processor 1112 of the illustrated example isin communication with a main memory including a volatile memory 1114 anda non-volatile memory 1116 via a bus 1118. The volatile memory 1114 maybe implemented by Synchronous Dynamic Random Access Memory (SDRAM),Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory(RDRAM) and/or any other type of random access memory device. Thenon-volatile memory 1116 may be implemented by flash memory and/or anyother desired type of memory device. Access to the main memory 1114,1116 is controlled by a memory controller.

The processor platform 1100 of the illustrated example also includes aninterface circuit 1120. The interface circuit 1120 may be implemented byany type of interface standard, such as an Ethernet interface, auniversal serial bus (USB), and/or a PCI express interface.

In the illustrated example, one or more input devices 1122 are connectedto the interface circuit 1120. The input device(s) 1122 permit(s) a userto enter data and commands into the processor 1112. The input device(s)can be implemented by, for example, an audio sensor, a microphone, acamera (still or video), a keyboard, a button, a mouse, a touchscreen, atrack-pad, a trackball, isopoint and/or a voice recognition system.

One or more output devices 1124 are also connected to the interfacecircuit 1120 of the illustrated example. The output devices 1124 can beimplemented, for example, by display devices (e.g., a light emittingdiode (LED), an organic light emitting diode (OLED), a liquid crystaldisplay, a cathode ray tube display (CRT), a touchscreen, a tactileoutput device, a light emitting diode (LED), a printer and/or speakers).The interface circuit 1120 of the illustrated example, thus, typicallyincludes a graphics driver card, a graphics driver chip or a graphicsdriver processor.

The interface circuit 1120 of the illustrated example also includes acommunication device such as a transmitter, a receiver, a transceiver, amodem and/or network interface card to facilitate exchange of data withexternal machines (e.g., computing devices of any kind) via a network1126 (e.g., an Ethernet connection, a digital subscriber line (DSL), atelephone line, coaxial cable, a cellular telephone system, etc.).

The processor platform 1100 of the illustrated example also includes oneor more mass storage devices 1128 for storing software and/or data.Examples of such mass storage devices 1128 include floppy disk drives,hard drive disks, compact disk drives, Blu-ray disk drives, RAIDsystems, and digital versatile disk (DVD) drives.

Coded instructions 1132 to implement the methods of FIGS. 6-10 may bestored in the mass storage device 1128, in the volatile memory 1114, inthe non-volatile memory 1116, and/or on a removable tangible computerreadable storage medium such as a CD or DVD.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

1. An apparatus comprising: a radio-frequency identification tag to beoperatively coupled to a field device of a process control system, theradio-frequency identification tag having a processor, an onboardmemory, and an antenna, the onboard memory to store data received fromthe field device to be communicated to a radio-frequency identificationreader, wherein power for the processor and the onboard memory is to bedrawn from control system power provided to the field device.
 2. Theapparatus of claim 1, wherein the radio-frequency identification tag isto communicate with the radio-frequency identification reader at adistance of up to about 90 feet.
 3. The apparatus of claim 1, whereinthe radio-frequency identification tag is to communicate with theradio-frequency identification reader at a distance of up to about onefoot when the control system power is unavailable, the radio-frequencyidentification tag to be powered by the radio-frequency identificationreader via electromagnetic induction.
 4. The apparatus of claim 1,further comprising a power manager to draw the power provided to theprocessor and the onboard memory from the control system powerassociated with the field device.
 5. The apparatus of claim 4, whereinthe power manager includes a signal conditioner to enable the powermanager to draw the power without disrupting a signal transmitted onsignal wires.
 6. The apparatus of claim 1, wherein the control systempower corresponds to loop power.
 7. The apparatus of claim 1, whereinthe control system power corresponds to network power.
 8. The apparatusof claim 1, wherein the onboard memory is a magnetoresistiverandom-access memory.
 9. The apparatus of claim 1, further comprising acapacitor to store power scavenged from the control system powerprovided to the field device.
 10. The apparatus of claim 1, wherein theantenna is powered from an electromagnetic field generated by theradio-frequency identification reader.
 11. The apparatus of claim 1,wherein the antenna is powered from the control system power to enablewireless broadcast transmissions of the data.
 12. The apparatus of claim1, wherein the onboard memory stores data uploaded from aradio-frequency identification writer for subsequent retrieval by theradio-frequency identification reader.
 13. An apparatus comprising: aradio-frequency identification tag operatively coupled to a field deviceof a process control system, the radio-frequency identification tag tooperate in a semi-passive mode; and a power manager operatively coupledbetween the radio-frequency identification tag and the field device, thepower manager to draw power for the radio-frequency identification tagfrom control system power of the process control system.
 14. Theapparatus of claim 13, wherein the radio-frequency identification tag isto wirelessly communicate with a radio-frequency identification readerat a range of about 30 to 90 feet from the radio-frequencyidentification tag.
 15. The apparatus of claim 13, wherein the powermanager is scavenge power from the control system power withoutdisrupting a signal transmitted on signal wires.
 16. The apparatus ofclaim 15, further comprising a capacitor to store the power scavenged bythe power manager.
 17. The apparatus of claim 13, wherein theradio-frequency identification tag is to store data associated with thefield device, the radio-frequency identification tag to be physicallycoupled to the field device to enable an operator located local to thefield device to access the data.
 18. A method comprising: powering aradio-frequency identification tag operatively coupled to a field deviceof a process control system from control system power provided to thefield device; storing data associated with the field device on theradio-frequency identification tag; and wirelessly transmitting the datato a radio-frequency identification reader.
 19. The method of claim 18,wherein an antenna of the radio-frequency identification tag is poweredby an electromagnetic field generated by the radio-frequencyidentification reader when transmitting the data.
 20. The method ofclaim 19, wherein the radio-frequency identification tag is powered viathe antenna via the electromagnetic field generated by theradio-frequency identification reader when the control system power isunavailable.
 21. The method of claim 18, wherein the control systempower corresponds to loop power.
 22. The method of claim 18, wherein thecontrol system power corresponds to network power. 23-53. (canceled)